Overview
Doom
The Imp is the most common demon encountered in Doom games. While not particularly tough and rather slow in moving and shooting fireballs, Imps can attack from considerable distances and can create a deadly situation if they attack as a group.
The Doom manual colorfully describes the Imp as follows: “You thought an imp was a cute little dude in a red suit with a pitchfork. Where did these brown bastards come from? They heave balls o’ fire down your throat and take several bullets to die. It’s time to find a weapon better than that pistol if you’re going to face more than one of these S.O.B.s.”
Doom 3

The Doom 3 Imps are considerably different from their classic counterparts. Their bodies are now longer, thinner, and yet manage to be a fair amount tougher. While most of their feats of agility and wall-crawling are limited cutscenes, the Imps are considerably more versatile by hiding to ambush the player or even pouncing sideways occasionally to dodge attacks from the player. Like many of the Doom 3 enemies, the Imps are also able to teleport into an area to catch the player unawares.
Powers & Abilities
Imps primarily hurl balls of flaming plasma at players from a great range and can claw at them if they manage to get close enough. While their fireballs move quite slow and are relatively easy to dodge, they have a habit of catching a player off guard thanks to the length of their firing range, and can be especially dangerous when they attack in packs.
In Doom 3, the Imps become considerably more agile, even dodging attacks on certain occasions. They also become increasingly more stealthy due to their darker coloration and the dark atmosphere of most Doom 3 levels. Imps in Doom 3 can even be seen crawling on the walls of ceilings at times to ambush people. They now also possess an assortment of ten eyes to validate their ability to see the player from great distances and even in the dark.
Other Media
Doom (2005)

True to their nature, several Imps manage to appear in the 2005 Doom movie as they are the most common creature for people to mutate into.